1. Field of the Invention
The present invention relates to a recording/playback device, a recording/playback method and a digital broadcast viewing history recording system configured to allow for deleting unneeded portions contained even in copy-inhibited data without using copy processing.
2. Description of Related Art
In recent years, as the digital broadcast spreads, the demands have been increased for improved convenience of recording digital video content. It would be more convenient if a user can retain only needed portions of recorded digital content or delete the other portions, for example. With the improved convenience, a user can reduce unnecessary viewing time, as well as the capacity of a recording medium can be conserved. However, there are the following problems in realizing such convenience.
A first problem is in that digital content must be edited without using copy processing.
Digital content which is recorded by a recorder using an optical recording medium such as an HDD or a DVD and includes copy control for copyright protection can be moved, but not be copied, from a recording medium or device to another.
The copy control for copyright protection includes copy control by which a received digital broadcast signal can be recorded by digital recording equipment only once as in digital terrestrial broadcast. In that case, the recorded digital broadcast signal cannot be dubbed (copied) to other digital recording equipment. When recording equipment having a moving function is used, once content is moved from a recording medium or device to another, the content is deleted from the source recording medium. For example, a TV program recorded on an HDD can be moved onto a DVD, then the TV program is deleted from the HDD.
Typically, when recorded digital content is edited, for example unneeded data such as a commercial message (CM) is edited out of the content, information of positions dividing the content is recorded and a playlist containing data of portions to be played back of the content is created based on the information of division.
A playlist contains only information listing positions to start playback, hence not the content itself. If a user desires to create content data that can be played back similarly to the portions to be played back listed in the created playlist, it is necessary to create replicated data by copying content data referenced by the playlist based on the playlist.
A second problem is in that if a user desires to decide unneeded portions of recorded video content, the user needs to know in advance where and what details are recorded in the content.
In order to decide unneeded portions of content, a user may view the details of the content actually for confirmation. However, this approach leads to viewing the content thoroughly, therefore being a time-consuming and labor-intensive task. The producing of the division information by editing out CMs, for example, can be realized by detecting a change in a video signal, an acoustic signal and the like or by detecting a silent portion. However, this approach does not ensure that a user can specify desired division points. Further difficulty is in that different users add division information to different positions. Furthermore, since the producing of only the division information cannot make the purpose of the division clear, it is difficult to utilize the division information effectively afterward.
Prior arts relating to the deletion of unneeded data include the Japanese Patent Laid-Open No. 2003-61036, for example. According to that patent document, specifically to FIG. 1 therein, in the relation between a service center and a user subscribing to the center in a pre-determined manner, encrypted index information supplied from the service center is received by a user's TV program recording/playback device, a received encrypted signal is decoded by an index information decoder to produce index information, and the produced index information is displayed on a display device for presentation to the user. The document further describes that based on the displayed details, the user specifies a playback method for a TV program signal from which a broadcast wave is received and recorded by a user operation; and according to the specified playback method, the TV program recording/playback device operates such as to skip, for example CMs in a recorded TV program to play back program content, or to cue a pre-determined position in the program content to start playback from that position.
The method proposed by the prior art realizes playback according to a user-specified playlist (playback list). The method just retains the original recorded video content recorded by the user's TV program recording/playback device and performs the playback and display by skipping unneeded portions. That is, the method does not delete CMs from a recording medium to conserve the capacity of the recording medium.